Field of the Technology
The present disclosure generally relates to equipment and techniques for milling. The present disclosure more specifically relates to equipment and techniques adapted for milling railway rails.
Description of the Background of the Technology
Railways networks are in use throughout the world for freight and transit alike. Over time, railway rails become worn and irregularities may arise, especially along the railhead profiles. Consequently, railways must be maintained by either replacing or re-profiling worn or deformed rails. For example, rail re-profiling may be undertaken to address common rail deformities such as rail corrugation, which may comprise short to long wavelengths. Corrugations are known to cause noise, vibrations, and premature wheel wear. Rail re-profiling may also be undertaken as part of a regular maintenance schedule aimed at extending the operational life of rails.
To minimize interference with rail traffic and to reduce labor costs, it is often advantageous to re-profile worn rails in situ. While in situ re-profiling may avoid extended offline periods, present re-profiling strategies comprising planing, grinding, and, more recently, peripheral milling are generally slow and/or hazardous endeavors. For example, rail grinding may employ one or more grinding wheels mounted to a rail grinding vehicle. Rail grinding vehicles are known to produce significant quantities of sparks during the grinding process, which may present a significant fire hazard along the railway at its periphery. Conventional rail re-profiling vehicles also are known to produce chatter and may be unable to produce desirable smooth and continuous railhead profiles. Certain conventional rail milling vehicles employ peripheral milling techniques to mill a predetermined profile on the rails. While presenting less fire risk than rail grinding vehicles, rail milling vehicles typically advance along the railway slowly and may require that the railway be taken out of service for an extended period. Rail milling vehicles also may be unable to continuously mill rail. For example, peripheral milling cutters used on such vehicles are designed to form a specific railhead profile and, therefore, are unable to adequately adapt to changing rail conditions such as variations in the railhead profile, curves, or transitions (such as, for example, railway grade crossings). Consequently, the conventional rail milling process may be slowed in order to adjust or replace milling cutters to match the rail profile variations, adapt to changes in the condition of the rails, or address curves or transitions. In some instances, large sections of railway must be ignored or are inadequately milled due to variations or transitions.
Given the foregoing drawbacks, it would be advantageous to develop improved techniques for rail re-profiling.